Speaker cabinet and speaker using the same

ABSTRACT

A speaker cabinet according to an embodiment of the present invention includes: a pair of side plates whose outer peripheral portions define no apexes; and a bent plate curved in conformity with the outer peripheral portions of the pair of side plates and mounted to the pair of side plates.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a speaker cabinet and a speaker usingthe same. To be more specific, the present invention relates to aspeaker cabinet and a speaker using the same capable of producing asound image space more natural and full of reality.

2. Description of the Related Art

The design principles for speaker cabinets have been polarized into twoways of thinking: the concept that the radiation sound from the cabinetis unnecessary and should be suppressed so as to reverberate as littleas possible; and the concept that the radiation sound from the cabinetshould be positively allowed to reverberate to attain a rich,full-bodied sound. As means for realizing the latter concept, thethickness of the plate materials forming the cabinet is reduced, orwell-reverberating plate materials are used. For example, there has beenproposed a cabinet whose plate materials are composed of resonancematerials for musical instruments (see Japanese Utility ModelApplication No. Hei 6-23394). According to Japanese Utility ModelApplication No. Hei 6-23394, a front plate and a back plate are attachedto a body portion formed of a cylindrical member to form a hollowcylindrical cabinet, and a speaker unit is mounted to the centralportion of the front plate of the cabinet, thereby realizing a speakerproducing a natural sound.

However, the speaker cabinet as disclosed in Japanese Utility ModelApplication No. Hei 6-23394 has the following problems. That is, of theradiation sounds from the resonance portions of a musical instrumentsuch as a guitar, the radiation sound from the front plate (and the backplate) is larger than the radiation sound from the body portion. This isdue to the fact that the front plate (and the back plate) are formed ofa relatively thin plate material (typically having a thickness ofapproximately 3 mm) and that the musical instrument has a so-called drumstructure whose body portion constrains the peripheral portion and whosecentral portion is easily allowed to vibrate. As a result, the vibrationof the strings is richly flavored, and a full-bodied timbre is obtained.In contrast, in the speaker cabinet as disclosed in Japanese UtilityModel Application No. Hei 6-23394, it is necessary to impart anappropriate strength allowing supporting of the speaker unit to theportion where the speaker unit is mounted (that is, front plate of thecabinet, which corresponds to the front plate of the guitar), so thethickness of the plate material must be increased. As a result, theradiation sound from the front plate is reduced, and no full-bodiedsound is reproduced. If the cabinet is prepared with the thickness ofthe front plate being almost as thin as that of a musical instrument,the requisite strength for supporting the speaker cannot be obtained,which means that there are cases where the cabinet cannot be put intopractical use, and the weight of the speaker must be limited (that is,use of a high-power speaker is impossible). Further, if, in such acabinet, the drive power for the speaker unit is increased, an abnormalvibration of the front plate will be caused in some cases, resulting ingeneration of noise. Even if the speaker unit is mounted in asatisfactory manner, the weight of the front plate as a whole increasesdue to the weight of the speaker unit itself, so the vibration of thefront plate is rather limited, and no full-bodied sound can bereproduced.

SUMMARY OF THE INVENTION

The present invention has been made in view of solving theabove-mentioned problems. It is therefore an object of the presentinvention to provide a speaker cabinet and a speaker using the samecapable of producing a sound image space more natural and full ofreality.

A speaker cabinet according to an embodiment of the present inventionincludes: a pair of side plates; and a bent plate curved in conformitywith outer peripheral portions of the pair of side plates and mounted tothe pair of side plates.

In one embodiment of the invention, amounting assisting member isprovided at a mounting portion between each of the side plates and thebent plate.

In another embodiment of the invention, an opening is provided in atleast a part of the bent plate and the side plates.

In still another embodiment of the invention, the speaker cabinetfurther includes an auxiliary baffle plate provided at least on an innerside of a front portion of the bent plate.

A speaker cabinet according to another embodiment of the presentinvention includes: a pair of side plates whose outer peripheralportions define no apexes; and a bent plate curved in conformity withthe outer peripheral portions of the pair of side plates and mounted tothe pair of side plates.

In one embodiment of the invention, each of the side plates has a linearfront portion, a linear bottom portion, and a curved rear portion, andwherein the front portion, the bottom portion, and the rear portion arecontinuous with each other to form the outer peripheral portion, withoutapexes being defined in portions where they are connected with eachother.

According to another aspect of the invention, a speaker system isprovided. The speaker system have the above-described speaker cabinetand at least one speaker unit mounted to a front portion of the bentplate of the speaker cabinet.

According to the present invention, instead of forming arectangular-parallelepiped-box-shaped cabinet by attaching four platesincluding a front plate, a top plate, a rear plate, and a bottom plateto side plates, a cabinet is formed by curving a single bent plate.Owing to the adoption of this construction, the vibration of the sideplates is predominant, and abnormal vibration of the bent plate(corresponding to the front plate or the front side) to which thespeaker unit is mounted can be markedly suppressed. Further, thevibration of the side plates is caused by the transmission of thevibration from the speaker unit through the main body and the inner air,so by forming the side plates as continuous curved surfaces using thinmaterials, it is possible to increase this vibration. As a result, asignificantly full-bodied sound image space is formed. To be morespecific, while an attempt has conventionally been made to realize aspeaker in which the speaker unit corresponds to the strings of aguitar, which is the sound source of the guitar, with the speaker unitbeing mounted to the portion corresponding to the front plate of theguitar, such a speaker makes scarcely any use of the effect of thespatial structure of the guitar since the speaker unit is far heavierthan the guitar strings. In contrast, according to the presentinvention, the speaker unit is mounted to a bent plate (portioncorresponding to the body portion of an acoustic guitar), whereby it ispossible to vibrate the portions corresponding to the front plate andthe back plate of an acoustic guitar (that is, side plates 11 and 12) ina significantly satisfactory manner, thereby making it possible toreproduce a sound making full use of the effect of the spatial structureof an acoustic guitar (structure allowing rich flavoring of the faintvibration of the strings). As a result, it is possible to reproduce asound that is significantly natural and full of reality.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are schematic perspective views illustrating a speakersystem using a speaker cabinet according to a preferred embodiment ofthe present invention;

FIG. 2 is a schematic sectional view taken in the direction of a sideplate of the speaker system of FIGS. 1A and 1B;

FIG. 3 is a schematic sectional view of a speaker system according toanother embodiment taken in the direction of a side plate thereof;

FIG. 4 is a schematic view of a mounting portion between a side plateand a bent plate in a speaker cabinet according to a preferredembodiment of the present invention;

FIG. 5 is a schematic diagram showing a vibration mode simulation resultof a speaker according to an example of the present invention; and

FIG. 6 is a schematic diagram showing a vibration mode simulation resultof a speaker according to a comparative example.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In the following, preferred embodiments of the present invention will bedescribed with reference to the drawings. The present invention,however, is not restricted to these embodiments.

FIG. 1A is a schematic perspective view of a speaker system using aspeaker cabinet according to a preferred embodiment of the presentinvention, and FIG. 1B is a schematic perspective view illustrating thespeaker system with its side plates detached. FIG. 2 is a schematicsectional view taken in the direction of a side plate of the speakersystem of FIGS. 1A and 1B. FIG. 3 is a schematic sectional view of aspeaker system according to another embodiment taken in the direction ofa side plate thereof. First, a speaker cabinet will be described. Aspeaker cabinet 10 is composed of a pair of side plates 11 and 12 and asingle bent plate 13 mounted thereto. The side plates 11 and 12 includeportions whose outer peripheral portions define no apexes (that is,smoothly continuous portions). In the example shown, both the sideplates 11 and 12 have a configuration whose outer peripheral portiondefine no apex. The bent plate 13 is mounted in a form in which it iscurved in conformity with the outer peripheral portions of the sideplates 11 and 12. One of the features of the present invention is that acabinet is formed not by attaching four plates of a front plate, a topplate, a rear plate, and a bottom plate to side plates but by curving asingle bent plate. By adopting this construction, the vibration of theside plates is predominant, and any abnormal vibration of the bent plate(corresponding to the front plate or the front side) to which thespeaker unit is mounted can be markedly suppressed. That is, it ispossible to secure the requisite mounting strength for the speaker unitand, at the same time, to positively vibrate the cabinet. As a result,it is possible to form a significantly full-bodied sound image space.

The side plate 11 will be specifically described (the description alsoapplies to the side plate 12). Typically, the side plate 11 has a frontportion 11 a, a bottom portion 11 b, and a rear portion 11 c, which forma continuous outer peripheral portion such that no apexes are defined inthe connecting portions between them (that is, the connecting portionsare of a smooth, arcuate configuration). By using such a side plate, itis possible to attach a single curved bent plate to the side plate.Preferably, as shown in FIG. 1B, the front portion 11 a and the bottomportion 11 b of the side plate are linear, and the rear portion 11 cthereof is curved. As a result of curving the rear portion of the sideplate (that is, providing the side plate with a contour extending in acurved line), the rear portion of the bent plate mounted in conformitywith the outer peripheral portion of the side plate is also curved. As aresult, it is possible to avoid interference with the vibration of soundwaves while maintaining the requisite strength for the enclosure.Further, the vibration emanated from the speaker unit is transmitted tothe side plates through the cabinet main body and the inner air, therebymaking it possible to vibrate them in a significantly satisfactorymanner. Thus, it is possible to obtain a speaker cabinet having astrength high enough for practical use and capable of producing afull-bodied sound. While, in the example shown, the side plates are flatplate, it is also possible for them to be of a configuration outwardlyconvex and tense. By adopting this construction, it is possible toenhance the function of the cabinet as a sub sound source, therebymaking it possible to radiate sound waves in a wider range. Further, itis also possible to provide the side plates with prop sticks andappropriately change the position and configuration thereof, therebyvarying the vibration characteristics of the side plates and endowingthe speaker cabinet with a character of its own in terms of tonequality.

Representative examples of the material used for constructing the sideplate and the bending plate include Sitka spruce, Engelman spruce,cedar, silver fir, Indian Rosewood, Brazilian Rosewood, HondurasRosewood, Madagascar Rosewood, Cocobolo, New Jacaranda, mahogany,Sapelli, Honduras Mahogany, core, maple, walnut, basswood, ash, ebony,Castor aralia, alder, Bubinga, spruce, Rosewood, German spruce,Ovangkol, cypress, birch, Khaya, sycamore, granadia, malinpa, andplywoods thereof. The materials, which can be used for bodies of theacoustic guitars, are preferred, and Sapelli, mahogany, spruce,Rosewood, and maple are more preferred. The present invention utilizesadvantages of a space structure of the acoustic guitar, so the use ofthe materials for acoustic guitars is extremely preferable in view ofmatching between the space structure and the material.

It is possible for the bent plate to have any appropriate thickness aslong as it can be curved in conformity with the outer peripheralconfiguration of the side plates and support the speaker unit.Typically, the thickness of the bent plate is 3 to 6 mm. The thicknessof the side plates is typically 2 to 4 mm. This formation of the cabinetof thin materials is based on a technical concept totally different fromthat of the conventional rectangular-parallelepiped-box-shaped cabinet.

Preferably, as shown in FIG. 2, an auxiliary baffle plate 14 is providedat least on the inner side of the front portion of the bent plate 13.There are no particular limitations regarding the way the auxiliarybaffle plate is mounted; typically, it is attached to the bent plate. Byproviding the auxiliary baffle plate 14, the thin bent plate is endowedwith strength allowing supporting of the speaker unit. As the materialof the auxiliary baffle plate, any appropriate material may be adoptedas long as it does not adversely affect the acoustic characteristics ofthe cabinet. To be more specific, in addition to various types ofveneer, plywood or MDF may be adopted. From the viewpoint of practicaluse, it is desirable for the cabinet of the present invention to beprovided with a pedestal portion 15 so that the vibration of the cabinetmay not be hindered when it is arranged, for example, directly on thefloor. In this case, it is desirable to provide a pedestal mountingportion 16 on the bottom portion of the bent plate 13. In an embodiment,as shown in FIG. 3, the auxiliary baffle plate 14 and the pedestalmounting portion 16 can be molded integrally. Preferably, the endportions and the edge portions of the auxiliary baffle plate 14 and thepedestal mounting portion 16 are subjected to so-called beveling. Withthis arrangement, it is possible to further reduce the influence of theauxiliary baffle plate 14 and the pedestal mounting portion 16 on theacoustic characteristics of the cabinet. Further, this helps to reducethe bonding area with which the bonding to the side plates is effected.

FIG. 4 is a schematic diagram illustrating a mounting portion betweenthe side plate 11 or 12 and the bent plate 13. As shown in FIG. 4, in apreferred embodiment of the present invention, a mounting assistingmember 17 is provided in the mounting portion between the side plate 11or 12 and the bent plate 13. Typically, the mounting assisting member 17is attached to the side plate 11 or 12 and the bent plate 13. By bondingthe side plate 11 or 12 and the bent plate 13 to each other through theintermediation of the mounting assisting member 17, it is possible tomaintain an appropriate bonding strength for the side plate 11 or 12 andthe bent plate 13 and to make the contact area between the side plate 11or 12 and the bent plate 13 as small as possible. Further, throughadjustment of the width of the mounting assisting member 17 andadjustment of the strength thereof by providing a slit, etc., it ispossible to secure the requisite strength for the speaker cabinet. As aresult, all the members constituting the cabinet vibrate without beingrestricted, and the vibration (e.g., distortion or twisting) of thecabinet as a whole due to their vibration ceases to be restricted. Thus,it is possible to obtain a speaker cabinet capable of producing asignificantly full-bodied sound. The mounting assisting member 17 mayextend over the entire mounting portion between the side plate 11 or 12and the bent plate 13 or over a part thereof. The configuration of themounting assisting member, the place where it is used, the number ofmounting assisting members used, etc. may be set appropriately inaccordance with the purpose or the nature of the desired sound.

As the material of the mounting assisting member 17, any appropriatematerial may be adopted as long as the effect of the present inventioncan be obtained. Typically, a soft wood is used, and preferably, amaterial for a reinforcing member (so-called lining) for the connectionbetween the frame portion and the front plate or the back plate of anacoustic guitar is used. Specific examples of the material include cedarand spruce. By using such material, the sound reproduced becomessignificantly natural and full of reality.

Preferably, an opening may be formed at least in a part of the bentplate and the side plates. Preferably, the opening may be formed in thefront portion of the bent plate. Such an opening can function as abass-reflex duct in a speaker and/or as the sound hole of an acousticguitar. By varying the configuration of the opening, the place where itis formed, and the number of such openings, it is possible to vary theresonance characteristics of the cabinet. Thus, by appropriately settingthem, it is possible to realize desired characteristics for the speakerto be obtained.

Referring again to FIG. 1, a speaker system according to a preferredembodiment of the present invention will be described. In a speakersystem 100 according to the present invention, at least one speaker unit(woofer 20 and tweeter 30 in the example shown) is mounted to the frontportion of the bent plate 13 of the speaker cabinet 10. The type and thenumber of speaker units mounted can obviously be changed according tothe purpose or the like. It is one of the remarkable features of thepresent invention that the speaker unit is mounted to a bent plate.

The present invention is not restricted to the preferred embodimentsdescribed above but allows any appropriate modifications as long as theeffects of the present invention can be attained. For example, while theside plates of the embodiment shown in FIG. 1 have no apexes, it is alsopossible for the side plates to partially substantially exhibit apexes.

In the following, the present invention will be described specificallywith reference to an example, which should not be construedrestrictively.

EXAMPLE 1

A piece of sapele plywood having a thickness of 4.5 mm was used as thebent plate, pieces of sapele having a thickness of 3 mm were used as theside plates, and an MDF having a thickness of 12 mm was used as anauxiliary baffle plate. Further, as the mounting assisting member, aspruce prop stick was attached to the mounting portion between the bentplate and each side plate. A woofer having a diameter of 10 cm was usedas the speaker unit. In this way, a speaker as shown in FIGS. 1A and 1Band FIG. 2 was prepared. The vibration mode of the thus-obtained speakerwas simulated through characteristic value analysis. In the simulation,there was obtained the ease with which vibration is effected, which isdetermined not by the way the speaker unit is mounted but by theconfiguration of the cabinet itself. FIG. 5 shows a vibration mode inwhich a primary mode appears.

COMPARATIVE EXAMPLE 1

A conventional rectangular-parallelepiped-box-shaped speaker wasprepared. The front plate, the top plate, the rear plate, the bottomplate, and the pair of side plates were all formed of MDF having athickness of 10 mm. As the speaker unit, one similar to that of Example1 was mounted to the front surface. The vibration mode of thethus-obtained speaker was simulated through characteristic valueanalysis. FIG. 6 shows a vibration mode in which a primary mode appears.

As is apparent from comparison of FIGS. 5 and 6, in the speaker of theexample of the present invention, the vibration of the side plates ispredominant, and no split vibration or abnormal vibration is generatedin the bent plate. In contrast, as can be seen from FIG. 6, in thespeaker of the comparative example, in addition to the vibration of theside plates, split vibration is generated in the top plate and the frontplate, adversely affecting the reproduced sound.

The speaker cabinet of the present invention proves significantly usefulfor a speaker reproducing a natural and full-bodied sound.

1. A speaker cabinet comprising: a pair of side plates; and a singlebent plate curved in conformity with the entire outer peripheralportions of the pair of side plates and mounted to the pair of sideplates so that ends of the single bent plate meet.
 2. A speaker cabinetaccording to claim 1, wherein a mounting assisting member is provided ata mounting portion between each of the side plates and the bent plate.3. A speaker cabinet according to claim 1, wherein an opening isprovided in at least a part of the bent plate and the side plates.
 4. Aspeaker cabinet according to claim 1, further comprising an auxiliarybaffle plate provided at least on an inner side of a front portion ofthe bent plate.
 5. A speaker system having the speaker cabinet accordingto claim 1, the speaker system further comprising at least one speakerunit mounted to a front portion of the bent plate.
 6. A speaker cabinetaccording to claim 1, wherein a material for constructing the side plateand the bent plate is selected from the group consisting of Sitkaspruce, Engelman spruce, cedar, silver fir, Indian Rosewood, BrazilianRosewood, Honduras Rosewood, Madagascar Rosewood, Cocobolo, NewJacaranda, mahogany, Sapelli, Honduras Mahogany, core, maple, walnut,basswood, ash, ebony, Castor aralia, alder, Bubinga, spruce, Rosewood,German spruce, Ovangkol, cypress, birch, Khaya, sycamore, granadia,malinpa, and plywoods thereof.